The present disclosure relates generally to systems and methods for recycling lead-acid batteries, and more specifically, relates to recycling the lead content from lead-acid batteries.
The lead present in a lead-acid battery may be in a number of forms. For example, a lead-acid battery may include grids, plates or spines of lead or lead alloys, battery paste that contains metallic lead sponge, lead oxides, and/or lead sulfates, and posts and/or interconnects that contain metallic lead and/or lead alloys. While it may be desirable to attempt to recover lead from the waste of spent or retired lead-acid batteries, this material may include a variety of lead compounds (e.g., lead alloys, oxides, sulfates and carbonates) and an array of physical and/or chemical impurities. Existing methods for purifying lead typically rely almost entirely on multi-stage pyrometallurgical smelting, in which some of these compounds are combusted to produce volatile gases, some of which must be scrubbed (e.g., captured and removed from the exhaust stream) to prevent release, in accordance with environmental regulations, and subsequently the remaining impurities are removed from the metallic lead in various refining operations. Since these operations often require specialized equipment and certain consumables (e.g., solutions or other refining agents), this refinement process generally adds cost and complexity to the lead recovery process. For the construction of new lead acid batteries, the resulting refined lead should have purity in excess of 99% Pb. This highly refined lead is then converted to a mixture of lead and lead oxide as the first stage in producing the active material for new lead acid batteries.